Infection with human papillomavirus (HPV) has been clearly established as the central cause of cervical cancer. Indeed, certain oncogenic types of HPV can infect the cervix (part of the uterus or womb). This infection may go away by itself, but if it does not go away (this is called persistent infection), it can lead in women over a long period of time to cancer of the cervix. This study will evaluate the efficacy in prevention of persistent HPV-16 or HPV-18 cervical infection lasting at least 6 months, the immunogenicity and safety of GSK Biologicals HPV-16/18 vaccine (Cervarix TM ) over 24 months in Japanese adult women aged 20 - 25 years of age at study start. Approximately 1000 study subjects will either receive the HPV vaccine or a control vaccine (Hepatitis A vaccine) administered intramuscularly according to a 0-1-6 month schedule.